weather fieldwork

Question 1

what are some precautions of using thermometer

Answer 1

1. Hold thermometer 1.5m above ground - take temperature of air, not ground
2. Reading thermometer at eye level - prevent parallax error
3. Hold thermometer away from body - measures air temp, not body temp
4. Not touching the glass tube of thermometer - prevent heat from bodies increasing temp readings

Question 2

how does swirling psychrometer work to measure RH

Answer 2

consists of dry and wet bulb thermometer
Dry bulb (DBT): measures current air temp
Wet bulb (WBT): shows how much evaporation and cooling is taking place - thermometers are swung = water evaporates from wet cotton wick = cools WBT

-> wet bulb depression (WBD): difference btwn WB and DB temperatures
function: used to find RH - compare dry bulb temp and WBD in table

-> The lower the relative humidity = the drier the air = the higher the evaporation rate from the wet cotton wick = the lower the temperature on WBT = bigger the WBD

Question 3

precautions of using swirling psychrometer

Answer 3

1. swing the sling psychrometer for at least one minute = ensure enough time for evaporation to happen and cool WBT for accurate WB

Question 4

precautions of using rain gauge

Question 5

how do we use anomemeter to measure wind speed

Answer 5

Hold the anemometer in open area with wind = wheel will rotate according to speed of wind = number of rotations is counted = used to calculate wind speed
Stronger the wind, faster the wheel rotates

Question 6

precautions using anomemeter

Answer 6

1. Place at a location without any obstructions to air flow (eg buildings, trees) -> can place at highest rooftop in the school
2. Ensure to stand at highest point possible, free of any obstructions = ensures good movement of air to obtain speed of wind

Question 7

precautions of windvane

Answer 7

1. Place at a location without any obstructions to air flow (eg buildings, trees) -> can place at highest rooftop in the school
2. Ensure to stand at highest point possible, free of any obstructions = ensures good movement of air to obtain speed of wind

Question 8

how do we use barometer to measure air pressure

Answer 8

Tune setting hand to sit directly above measuring hand → setting hand shows the air pressure at the start of the collection
Measuring hand will show the current air pressure when air pressure changes:
→ MH moves to left of SH = air pressure dropped
→ MH moves to right of SH = air pressure rose

Question 9

precautions of using barometer

Answer 9

1. Avoid placing barometer in draughty places like doors (cool air currents fluctuate) = AP is too variable to obtain reliable reading
   Avoid direct sunlight/heating (eg near heater) = will warm + expand metal cell in barometer = give false reading of falling AP -> data is not reliable

Question 10

strengths in data collection

Answer 10

1. multiple sites chosen = more variation (in weather conditions) = more representative of weather conditions in location = more reliable data
2. Taking multiple readings at each site, averaging results - minimise error in measurement = accurate data

Question 11

weaknesses in data collection

Answer 11

1. data collected at only one time = not good representation of weather conditions
2. data was collected in only one season = not good representation of weather conditions of location during other seasons
3. poor site selection –> too little sites chosen/external factor may be introduced (more than one changed variable) = not a good representation of weather conditions
4. taking turns to collect data = inconsistencies in handling equipment = data may not be reliable

Question 12

how to improve weaknesses

Answer 12

1. collect at multiple timings/days eg hourly data
2. collect over a few days in summer/winter/fall/spring
3. increasing the number of sites/choosing more varied sites/ensure sites chosen have one changed variable across
4. visit sites together and collect data together/standardise method of collecting data